With --noopt run unoptimized code through optimizer, more optimizations can be done later.

runtime/vm/debugger.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 1350 matching lines @@
   for (StackFrame* frame = iterator.NextFrame();
        frame != NULL;
        frame = iterator.NextFrame()) {
     ASSERT(frame->IsValid());
     if (FLAG_trace_debugger_stacktrace) {
       OS::PrintErr("CollectStackTrace: visiting frame:\n\t%s\n",
                    frame->ToCString());
     }
     if (frame->IsDartFrame()) {
       code = frame->LookupDartCode();
-      if (code.is_optimized()) {
+      if (code.is_optimized() && !Compiler::always_optimize()) {
         deopt_frame = DeoptimizeToArray(isolate, frame, code);
         for (InlinedFunctionsIterator it(code, frame->pc());
              !it.Done();
              it.Advance()) {
           inlined_code = it.code();
           if (FLAG_trace_debugger_stacktrace) {
             const Function& function =
                 Function::Handle(isolate, inlined_code.function());
             ASSERT(!function.IsNull());
             OS::PrintErr("CollectStackTrace: visiting inlined function: %s\n",
@@ skipping 1543 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart